Seals for slide out rooms in recreational vehicles, or other applications that require the sealing of openings that are exposed to outdoor elements, are often cumbersome in their use and installation. This is due to several factors. First, the openings for slide out rooms are not standard in that the wall thickness is not always uniform. This often forces the use of many seals to cover various wall thicknesses. It is also possible that the walls are not perfectly even in their thickness. Still further, the construction of recreational vehicles or other outer facing walls includes an inner substrate such as foam, wood or other insulating member that is covered on its exterior surface by a type of exterior covering or siding that is often fiberglass, plastic or metal. At the opening where a slide out room in a recreational is located, the edge of the opening must be finished and sealed to create an aesthetically pleasing and functional design. One way of accomplishing this is to place trim around the opening and then fit a seal to the opening. This can be time-consuming and requires multiple different materials and products that need to be cut, attached and then maintained. This creates inefficiencies in production and can increase cost. There exists a need in the marketplace, therefore, to provide a solution that both provides a visually appealing and functional way of finishing and sealing an opening of an exterior wall such as the opening in which a slide out room is located on a recreational vehicle.